This invention relates generally to an adapter device for facilitating the mounting of an electrical or electronic component to the terminals of a terminal block, and more particularly to a terminal bridging adapter for permitting the mounting of a plurality of such electrical or electronic components to a plurality of adjacent terminals on a matrix-type terminal block arrangement of the type used with key telephone systems.
Terminal bridging devices for mounting components to such matrix arrangements of terminals are generally known in the art. For example, U.S. Pat. Nos. 4,113,340; 4,116,524 and 4,126,369 disclose such devices. However, all of these prior art devices are directed to the mounting of components which are smaller in their transverse dimensions than the spaces available between the spaced parallel rows of terminals in such a terminal block. Hence, a problem has arisen with respect to mounting larger components to terminals in adjacent rows in such a terminal block assembly.
Prior to the invention of the devices set forth in the above-referenced U.S. patents, the addition of electrical or electronic components to such terminal blocks required the provision of independent mounting space for each component and the hand-running of suitable leads from appropriate terminals in the terminal block to the component. Such operation is labor-intensive, time-consuming and expensive. Moreover, the space generally allotted for telephone equipment is minimal and hence the addition of such other components is restricted.
Attempts have been made to remove terminals from the blocks and wire electric components directly to adjacent terminals. However, component lead wires are often of a larger diameter than the telephone lead wires commonly used and hence are difficult to maintain in acceptable electrical and mechanical contact with these terminals. Additionally, the labor of removing terminals from a terminal block and installation of electric or electronic components therein is difficult and expensive at best. Further, the removal of terminals from a block restricts the future usage of that block for later possible modifications.
While the adapter devices disclosed in the above-referenced U.S. patents have proven useful in solving a number of these problems, there remains room for improvement. In particular, these prior art devices cannot be used for the mounting of electrical or electronic components whose transverse dimensions are greater than the space normally provided between adjacent rows of terminals on such a terminal block assembly.
Such larger components may comprise fuses for example. In this regard, telephone equipment inside a building is usually protected from power transients caused by a lightning, damaged power lines or the like by a line protector device which is designed to shunt high potential to ground. However, damaging currents at less than the selected high voltage potential can and do occasionally fail to trip this protector device and thus may damage the telephone equipment. Moreover, even relatively large AC currents at large AC voltages may pass such a protector because the AC voltage swings between positive and negative values and hence fails to reach the preselected tripping potential of the protector. Additionally, some time delay is inherent in such protectors, whereby currents may "sneak" past the protector and damage the telephone equipment.
While a suitable 500- to 600-volt fuse would substantially prevent such "sneak" currents, such fuses are difficult to mount to standard terminal blocks. In particular, the spacing between rows of terminals on these blocks are commonly on the order of 0.200 to 0.250 inch centers, while such fuses are generally on the order of 0.300 inches in diameter. Hence, terminal bridging adapter devices of the type set forth in the above-mentioned U.S. patents will be ineffective in providing suitable mounting for such fuses. Advantageously, the present invention is particularly useful for providing a simple and inexpensive means for mounting such fuses to the terminals of such a terminal block assembly.